Oxidation of Aromatic Compounds: XIII. Oxidation of Unsymmetrically Substituted 1,3-Diarylpropynones in a System CF3CO2H-CH2Cl2-PbO2

Abstract

Oxidation of unsymmetrically sunstituted 1,3-diarylpropynones in a system trifluoroacetic aciddichloromethane-lead(IV) oxide proceeds through intermediate formation of cation radicals and occurs regio-and stereoselectively affording E-1,1,2,2-tetraaroylethenes. The highest yield of these compounds was obtained from 1,3-diarylpropynones containing electron-donor methoxy and methyl groups in the aromatic ring conjugated with the triple bond.

Extended Version of the Corey–Chaykovsky Reaction: Synthesis of 2,4-Substituted Furans by the Treatment of β-Dialkylamino Chalcones with Dimethylsulfonium Methylide

“…All of the reactions were carried out using freshly distilled and dry solvents from solvent stills. The known ketones 1a-m , o-r were prepared by the Sonogashira coupling of terminal alkynes with acyl chlorides according to described procedures . The known S , S -dithioacetals 4a , c , d were prepared by the reaction of the corresponding ketone with carbon disulfide and bromoethane according to described procedures .…”